Laundry dryers typically have a rotating drum through which air flows in order to dry washed laundry within the drum. The laundry may simply be wet but not washed, for example where a user wants to dry his or her clothes after being caught in a rain storm. The air is typically heated in order to carry more moisture from the laundry.
Laundry dryers come in two main types: vented and condenser. A condenser dryer removes the moisture in the exhaust air from the drum so that the air may be released into the same room as the dryer. A vented dryer exhausts the air into a vent duct connected to the dryer for release at a location where the moist air will not have significant adverse effects. Typically the vent duct allows for transportation of the moist air to the outdoors.
Vented dryers are typically more efficient than condenser dryers for the same cost. Condenser dryers are usually used in locations where vent ducts are impractical to install.
Vented dryers are typically designed for use with short runs of vent duct. If a vent duct is longer than that for which the dryer id designed then the flow through the vent duct may be reduced. In addition to exhausting moist air, dryers also exhaust lint from the drying process. Lint often collects in the vent duct. If the flow through the vent duct is reduced then more lint will collect in the vent duct. This further reduces the flow.
Reduced flow decreases the efficiency of the drying process. It can also increase heat build-up within the vent duct or dryer. This can result in a fire within the dryer or the vent duct. It is important to maintain air flow through the dryer and vent duct when heated in order to limit the risk of combustion.
Booster fans are typically provided in duct vent runs longer than the designed for the dryer. The booster fan helps to maintain proper air flow through the vent duct. Booster fans are typically designed to start when differential pressure within the vent duct is at or greater than a given amount indicating that the dryer is running. Similarly, the booster fan will turn off when the differential pressure is below that amount.
Improvements to, or alternatives for, existing dryer and booster fan systems, dryers, dryer venting systems and dryer/dryer venting combinations, and methods related thereto are desirable.